The boxer and G-Unit's head honcho have been going at it, most recently after 50 Cent challenged Mayweather to read a page from Harry Potter-mocking Mayweathers um, literacy.

While filming for his new boxing documentary with Showtime All Access, Mayweather answered a fans question regarding 50 Cents challenge. While walking through a casino, a fan shouted "I heard 50 Cent challenged you for 750 thousand" Mayweather retorted "That's all he challenged me? He gotta raise the stakes!" Mayweather even threw in a jab at 50 yelling "Does he still make music? I haven't heard him in a while?"

Guess Mayweather didn't get wind of G-Units new EP The Beauty Of Independence yet.